Double Submit Cookies Pattern Cookies Another solution for CSRF.This pattern is a more lightweight implementation of CSRF-protection. While relatively new and generally considered somewhat untested (it’s just as effective as the Synchronizer Token Pattern in my opinion; the arguments against it are weak at best), it achieves protection while avoiding the use of state. The implementation of this pattern, like the Synchronizer Token Pattern, produces design and security consequences: Cookies cannot be tagged as HTTPONLY. Potential XSS vulnerabilities in subdomains can introduce poisoned cookies in upper domains. Cookies that contain sensitive server metadata, such as session cookies, should be tagged as HTTPONLY. This prevents client-side scripts from reading values from the cookie, adding a layer of protection. Given that this pattern requires client-side scripts to read the token from the cookie and apply it to the HTTP header, we cannot tag the cookie...
